In recent years, light is utilized as an essential element in every field of industry. This is because light has excellent properties such as an ultrahigh speed, an ultrawide band, noninvasiveness, and so on. Especially the ultrahigh speed is a unique property, as there is no phenomenon faster than light. Industrially, this property is considered as extremely important in ultrahigh-speed optical communication and the like. On the other hand, since there is no phenomenon faster than light, when measuring a transient change of state of light itself, a method of repeatedly performing measurement is often used. Aside from the measurement repetition method, there is also a method of performing measurement in a single shot. Examples of the single-shot measurement method include a method of using a streak camera that performs measurement by forcing a deflection of light, and a method of using ultrafast interference (optical spectrogram scope) with reference light (for example, see Patent Reference 1).    Patent Reference 1: Japanese Patent No. 3018173